The present invention is directed to an absorbent product having at least a top layer, an absorbent core, and a breathable outer cover material. A low to moderately breathable laminate, disposed between the absorbent core and the more breathable outer cover, reduces dampness on the outer surface of the breathable outer cover material without negatively increasing skin hydration of the wearer.
Absorbent articles, such as diapers, child training pants, adult incontinence garments, swim wear and the like, typically include at least a liquid-permeable top layer for direct contact with the wearer, an absorbent core layer, and a substantially liquid-impermeable outer cover material. The absorbent core is positioned between the top layer and the outer cover material. When the absorbent article is exposed to a liquid insult, liquid passes through the top layer and into the absorbent core. The outer cover prevents the liquid in the absorbent core from leaving the garment.
Many of today""s absorbent garments utilize breathable outer cover materials. Breathable outer cover materials are substantially impermeable to liquids, but are permeable to water vapor. Breathable outer cover materials permit escape of water vapor from the absorbent garment, increasing the garment comfort and reducing skin rashes and other irritations that result when water vapor is trapped inside the garment and heated by the wearer""s body. Many of today""s absorbent garments are highly breathable, for maximum wearer comfort.
One shortcoming of breathable absorbent articles is a cold, damp, clammy feel that often occurs on the outside of the garment, i.e., on the outside of the outer cover material. As liquid water in the absorbent core evaporates and passes through the outer cover material, the associated evaporative cooling causes a lowering of temperature of the absorbent core and adjacent outer cover material, resulting in a clammy, damp-feeling outer cover. There is thus a need or desire in the absorbent garment industry for absorbent articles which are highly breathable, yet which reduce or avoid the perceived dampness caused by evaporative cooling, while maintaining low levels of skin hydration.
The present invention is directed to an absorbent article having a breathable outer cover material and reduced perceived outer cover dampness. The absorbent article includes at least a liquid-permeable top layer, a breathable, substantially liquid impermeable outer cover material, and an absorbent core layer between the top layer and the outer cover material. In accordance with the invention, a low to moderately breathable laminate, including at least a low to moderately breathable film and a nonwoven filament web, is interposed between the absorbent core and the breathable outer cover material. This inner breathable laminate has a breathability which is lower (i.e., lower water vapor transmission rate) than the breathable outer cover material. Preferably, the inner laminate is placed with its film layer facing the absorbent core, and with its nonwoven web layer facing the outer cover material.
The presence of the low to moderately breathable inner laminate reduces perceived dampness of the exposed surface of the outer cover material without significantly reducing moisture flux through the diaper in use, thus maintaining skin health. The film of the inner laminate acts to partially reduce the flux out of the diaper arising from moisture leaving the absorbent core. At the same time, pathways for moisture to leave the skin are maintained, including pathways leading from the skin, around the absorbent core, through an air gap provided by the nonwoven web of the inner laminate, and out the breathable outer cover. The moisture transfer from the skin to the outer cover is actually enhanced, since there is less competition between moisture in the core and moisture in the skin to leave the diaper. In other words, since less moisture in the core is transferred to the air gap provided by the nonwoven web, that air gap is drier; thus, there is a stronger concentration gradient from the air adjacent to the skin, where the humidity is high, to the air gap, where the humidity is lower. This results in increased (ordinary) diffusion of water molecules from the skin to the air gap. Similarly, convective forces caused by movement such as a baby""s breathing would also drive moisture away from the skin and into the air gap with an additive result. The drier air gap provides better insulation, causing further reduction in the perceived dampness or clamminess.
With the foregoing in mind, it is a feature and advantage of the invention to provide an absorbent article having a relatively highly breathable outer cover layer and a low or moderately breathable inner laminate which, in combination, after being subjected to a liquid insult, exhibit reduced moisture transfer from the absorbent core through the breathable outercover, thus reducing total moisture flux out of the absorbent article compared to prior art absorbent articles.
It is a further feature and advantage of the invention to maintain pathways for moisture transfer away from the skin, wherein skin hydration levels remain low, possibly lower than conventional highly breathable diapers.
It is also a feature and advantage of the invention to provide a drier air gap between the absorbent core and outer cover, resulting in better insulation and a reduction in perceived outer cover dampness.
It is also a feature and advantage of the invention to provide diapers, child training pants, adult incontinence garments, swim wear, and other (e.g. medical) absorbent products which embody the features of the improved absorbent article of the invention.
The foregoing and other features and advantages will become further apparent from the following detailed description of the preferred embodiments, read in conjunction with the drawings. The detailed description and drawings are intended to be illustrative rather than limiting, the scope of the invention being defined by the appended claims and equivalents thereof.